Page 22 - Leshobo Technical Report_October2016

It generally consists of basal giant dolomite domes, curly algal mat limestone, clastic
algal mat laminated limestone and dolomite, argillite, SH-I algal mat limestone,
dolarenite, potsherd breccia, crinkle laminated dolomite, columnar stromatolites (LLH-C
and SH-C), oolites and quartz arenites (Beukes, 1978; Beukes, 1987). It is approximately
200 m thick in surface outcrops. Beukes (1987) interpreted this formation as a shelf
deposit while Altermann and Herbig (1991) interpreted it as shallow marine based on
stromatolite occurrences and morphology. It is subdivided into three members i.e.
Loodaarrug, Baviaanskrans and Motiton Members. The boundary between the
Monteville and the overlying Reivilo Formation is taken at the top of the last continuous
quartz arenite unit present in the succession. (Beukes, 1987; Altermann and Siegfried,
1997).
The lowermost Loodaarrug Member consists of alternating units of curly algal mat
limestone, clastic algal mat laminated limestone and dolomite and argillite. Thin units of
SH-I algal mat limestone, dolarenite and potsherd breccias are present. The base of the
member is formed through a 3.5 m thick unit of giant dolomite domes.
The middle Baviaanskrans Member is characterised by crinkle laminated and SH-C
columnar stromatolitic dolomite, oolitic carbonate rocks, potsherd breccias and
argillite. Several lenses of limestone are present in the dolomites.
The uppermost Motiton Member consists of quartz arenites, argillite, quartz
arenite-argillite, columnar stromatolitic dolomite (LLH-C and SH-C) and dolomitic quartz
arenite.

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